FIG. 18 schematically shows a conventional method for manufacturing an optical display unit to be incorporated into a liquid crystal display device. First, an optical film manufacturer produces a continuous sheet material, which includes an optical member, in the form of a material roll (#1). Examples of the “continuous sheet material” include a raw polarizing plate, a raw laminated film of a polarizing plate and a retardation plate, and so on for use in the production of liquid crystal displays. The material roll is then slit into a predetermined size (a size according to the size of a substrate) (#2). The slit piece of the continuous material is then cut into a specific length according to the size of the substrate to be bonded (#3). The specific-length piece of the sheet material is then subjected to an appearance inspection (#4). The finished product is then inspected (#5). Subsequently, the four end faces of the piece of the sheet material are worked (#6). The working is performed to prevent the adhesive or the like from coming out of the end faces in transit. The piece of the sheet material is then subjected to clean packaging in a clean room environment (#7). Subsequently, packaging for transportation (transport packaging) is performed (#8). The piece of the sheet material manufactured as described above is transported to a panel processing manufacturer.
The panel processing manufacturer unpacks the piece of the material sheet transported (#11). An appearance inspection is then performed to check whether scratches, stains or other defects are produced in transit or during unpacking (#12). The piece of the sheet material determined as non-defective in the inspection is then transferred to the next step. This appearance inspection may be omitted in some cases. The substrate (such as a glass substrate with a sealed liquid crystal cell) to which the piece of the sheet material will be bonded is previously manufactured and cleaned before the bonding step (#13).
The piece of the sheet material and the substrate are bonded together to form an optical display unit (#14). The release film is peeled off from the piece of the sheet material so that the adhesive can be left, and one side of the substrate is bonded to the surface of the adhesive. The other side of the substrate may also be bonded in a similar manner. A bonded state inspection and a defect inspection are then performed (#15). The optical display unit determined as non-defective in the inspection is transferred to an implementing step and implemented into a liquid crystal display device (#16). On the other hand, the optical display unit determined as defective is subjected to a reworking process (#17). In the reworking process, the optical member is peeled off from the substrate. A new optical member is bonded to the reworked substrate (#14).
The manufacturing process described above particularly requires the steps of working the end faces, packaging the piece of the sheet material, and unpacking the material, because the optical film manufacturer and the panel processing manufacturer are located at different places. However, such a multi-step process has the problem of an increase in manufacturing cost. There are also problems in which scratches, dust, stains, and so on can be caused by the multi-step process or the transportation so that an inspection process can be necessary, and problems in which different types of sheet materials must be carried and managed.
Japanese Patent Application Laid-Open (JP-A) No. 2007-140046 (Patent Literature 1) discloses a method for solving the problems. According to the publication, a sheet material including an optical member is drawn from a roll thereof, and whether the sheet material has any defect is detected. Based on the result of the detection, the sheet material is cut into pieces. Subsequently, the release film is peeled off, and then the cut piece of the sheet material is bonded to a liquid crystal cell substrate. The above steps are arranged in a continuous manufacturing line. Therefore, a roll of the sheet material can be directly packaged and delivered, in contrast to the conventional method including stamping the sheet material into pieces, carefully packaging each piece of the sheet material after the stamping, and delivering it to a panel processing manufacturer. JP-A No. 2005-37416 (Patent Literature 2) proposes another continuous manufacturing method including cutting the members (e.g., a polarizing plate) of a sheet material other than a release film so that the sheet material can be kept continuous by means of the release film and bonding the cut piece of the sheet material to a substrate with the adhesive interposed therebetween, while peeling off the release film.
Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2007-140046.
Patent Literature 2: Japanese Patent Application Laid-Open (JP-A) No. 2005-37416.